"But a look at the facts leads us not only to avoid reconsidering our calculations, but to move on our intended path with greater confidence," he said.
The two sides have held several rounds of negotiations this year over Iran’s nuclear program, but the talks have not led to any substantive developments.
President Obama has urged for a diplomatic solution to the Iranian nuclear dispute, arguing that sanctions will lead to concessions from Tehran.
The United States and its allies say that Iran is seeking nuclear weapons, while Iran insists its nuclear program is for peaceful purposes only.
There’s evidence that the sanctions have impacted Iran’s economy, but thus far Iran has not agreed to halt its uranium production or take other conciliatory measures.
Khamenei hinted at some of the economic issues in Iran when he urged Iranian leaders not to publicly fight.
"The reality is that there are problems, however you must not blame them on this or that party," Khamenei was quoted by the semi-official Fars News Agency, according to Reuters. "Instead you must solve those problems with unity.
"You should avoid useless disputes and airing these disputes to help preserve the nation's unity ... and officials should know these actions will not bring them any honor or prestige among the people," Khamenei said.